FIELD OF THE INVENTION
The present invention relates to a peelable image recording member, an image forming apparatus of the image forming member and a reusing method of the image forming member. More particularly, it relates to an apparatus of removing an imaging member from the image forming member on which the imaging member is held by an image forming apparatus using an electrophotographic or heat transfer system, and a peelable image recording member, capable of repeating image formation due to use of an imaging member and removal of an image in accordance with a method of reusing the image forming member utilizing an image forming apparatus equipped with the device of removing the imaging member.
Recently, problems about the earth environment have come to the front and importance of protection of forest resources have been recognized and, therefore, saving of wood resources as paper raw materials has become an important problem. At present, papers once used are not disposed and reuse of them as waste papers have been advanced. Although reuse of waste papers is recovery of resources, there arose a lot of problems until reused papers are made. In case of recovering waste papers, particularly in a company, there are various problems with respect to leakage of confidential documents and data; working of recovery with dividing according to the kind of papers and conveyance; and place for gathering recovered waste papers and their storage. In case of reusing waste papers, the length of pulp fibers becomes short by pulping them again, which results in deterioration of quality. Also, a device for removing ink of the image part is required. Since a paper-making device per se is huge, complicated and expensive, no paper reuse is remotely possible by the individual and, therefore, paper reuse is compelled to rely on a certain specific company. If these recovery with dividing, conveyance, gathering and operation of a huge device are not efficiently conducted, an enormous quantity of energy is consumed (discharge amount of CO.sub.2 becomes large). As a result, an earth warming phenomenon caused by an increase in CO.sub.2 amount as one of problems about the earth environment may be further promoted.
As the method of solving these problems, a method of reusing by erasing the image on the paper once used has been disclosed. The method of erasing the image is roughly classified into two methods. That is, there have been suggested one method of reducing adhesive properties between an imaging member and a substrate (paper) using a releasing liquid prepared by mixing water or a solvent with a surfactant and applying heat and pressure to peel off the imaging member from the substrate in a wet system, and another method of peeling due to an outer force (e.g. heat, pressure, mechanical force, etc.) without using water and a solvent, or previously forming an image having small adhesive properties and then peeling the imaging member due to heat, pressure, mechanical force and the like in a dry system. The following examples further illustrate the method of solving the above problems in detail.
As the example using water and a surfactant, Japanese Patent Application Laid-Open (JP-A) Nos. 6-250569, 6-208318 and 6-250570 disclose a method of applying heat to an image recording material with being maintained an aqueous solution of a surfactant, hot-melting ink on the image recording material and peeling off ink using a releasing material. In the above references, however, wetting between the image holding material and aqueous solution is important and it is necessary to penetrate the aqueous solution into an interface between the hot-melt ink and image holding material. When solid images are present on both surfaces, the surface of the image holding material repels the aqueous solution, which does not penetrate and, therefore, an effect of improving the peelability between the imaging member and image holding material can not be obtained. As a matter of course, the situation is the same in case of peeling off the image on the OHP sheet. In case of reusing repeatedly the image, a toner remained without being removed is accumulated on the image holding material and, therefore, the quality of the substrate (paper) deteriorates. Since a large amount of heat are required for drying the paper wetted with the aqueous solution, an amount of energy consumed becomes larger and a running cost becomes larger. In case of the color image, a large amount of a toner is used on the total surface of the image holding material in comparison with the monochromic image and, therefore, the surfactant can not penetrate into the image holding material. As a result, an effect of peeling off the toner can not be obtained so that an image recording material can not be reused. Furthermore, when the color image is made again on the image holding material on which the toner is remained, color-developing properties are sometimes changed.
Japanese Patent Application Laid-Open (JP-A) Nos. 1-101576 and 1-101577 direct to a method of dissolving and removing a toner resin by applying or dipping a soluble solvent to the image recording material.
As the example using a solvent, Japanese Patent Application Laid-Open (JP-A) No. 4-300395 discloses a method of adhering a solvent to an image recording material using dipping, spraying or applying means, dissolving a toner in the image recording material and removing the dissolved toner using washing, sucking or adsorbing means to reuse the image recording material. These methods make it possible to remove the imaging member on the image recording material but have a problem such as influence of use of an organic solvent on safety and environment, enormous quantity of energy required for removing the solvent and curling of the paper after drying. Furthermore, there arose a new problem that the toner dissolved in the solvent is adhered again to the image recording material. As a result, the quality of the image holding material reused is not sufficient. Any way, an enormous quantity of energy is required for drying the releasing agent used to remove or erase the imaging member in a wet system. Since an additive (e.g. surfactant, etc.) contained in the releasing agent is accumulated in the image holding material by using repeatedly, an adverse influence is exerted on repeated image formation.
On the other hand, Japanese Patent Application Laid-Open (JP-A) Nos. 1-297294 and 4-67043 suggest an erasing method comprising applying a silicone sealing material on a coated paper in a small thickness, drying the coated material to form a paper (erasable paper) whose surface is releasing-treated, printing on this paper, coating the surface of the print with a hot-melt material (cleaning material) in the hot-melt state for the purpose of cleaning, cooling and then removing a print (e.g. letter image, etc.) together with the hot-melt material. This method had the following drawbacks. That is, the adhesive properties between an imaging member and a releasing agent are not sufficient and, therefore, the releasing agent transfers from the image recording material to the other medium such as transfer roll to exert an adverse influence on the following image formation. Furthermore, the image recording material can not be repeatedly used because the peelability of the image recording material changes due to transfer of the releasing agent. The image recording material subjected to the releasing treatment generally makes it possible to easily remove the imaging member from the substrate, but has a problem that the fixing properties to the substrate and traveling properties (conveying properties) of the substrate deteriorate due to the releasing treatment. Japanese Patent Application Laid-Open (JP-A) No. 6-219068 discloses a reusable recording medium obtained by applying a thermal modified material (e.g. fluorine-containing acrylate material, etc.), wherein adhesive properties between the substrate and imaging member become poor due to heating, to a heat transfer recording paper or impregnating the heat transfer recording paper with the thermal modified material. This recording medium has the same drawback as that of the image recording material subjected to the releasing treatment, and it is necessary to form the part, which is not subjected to the releasing treatment, by previously sealing both ends of the recording medium so as to obtain traveling properties of the recording medium.
Furthermore, according to the method of forming the releasing material on the image recording material as described above, the releasing material is formed on the recording material by dissolving the releasing material in an organic solvent and applying the resulting solution to a substrate or impregnating the substrate with the solution. Therefore, the releasing material is formed on the total surface of the recording material. Thus, the traveling properties and conveying properties of the recording material in the image forming device are serious problems and, furthermore, the writing properties are also serious problems because the releasing material is present even at the part where no image is present. Since the releasing material is generally expensive, a large amount of the releasing material is required in the applying or impregnating method. A low utilization efficiency leads to an increase in cost.